But though our thought seems to possess this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits, and that all this creative power of the mind amounts to no more than the faculty of compounding, transposing, augmenting, or diminishing the materials afforded us by the senses and experience . . . In short, all the materials of thinking are derived either from our outward or inward sentiment: the mixture and composition of these belongs alone to the mind and will.
Time was, I liked to knock the English empiricists hard, love them though I might. Nowadays, I think they, especially Mr. David Hume, had it just right as far as the Theory of Knowledge, aka epistemology goes. Consider this article (Abstract Thoughts? The Body Takes Them Literally) in the New York Times today. It’s all about how we don’t just “think” with our brains, where all our linguistic nattering goes on, but with our bodies. Indeed, our brains treat many abstract concepts quite concretely, as instances of physical activity, translated into linguistic metaphor.
As Hume would say, our most abstract ideas spring, eventually, if you trace them back far enough, from genuine physical sensations. As the psychologist Julian Jaynes remarked in an earlier chapter of his book, The Origin of Consciousness in the Breakdown of the Bicameral Mind,
… the relation between an analog map and its land is a metaphor.
That is, just as a paper map relates to the actual terrain as a linguistic metaphor to reality, so too do our abstract ideas relate to physical reality and sensation. (Maps are not as cut and dried as you might think, either!) Our ideas are, in the end, analogs, a notion that would have made Plato vomit, I think.
BTW, I most certainly do not recommend Jayne’s book, although the first chapter or two are masterful descriptions of what thinking is actually, as opposed to what epistemologists like to pretend it is. He was, however, a very creative fellow.